UnifiedSetTest.java

/*
 * Copyright (c) 2021 Goldman Sachs and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v. 1.0 which accompany this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 */

package org.eclipse.collections.impl.set.mutable;

import java.lang.reflect.Field;
import java.util.HashSet;
import java.util.Iterator;
import java.util.concurrent.Executors;

import org.eclipse.collections.api.list.MutableList;
import org.eclipse.collections.api.set.MutableSet;
import org.eclipse.collections.api.set.Pool;
import org.eclipse.collections.impl.block.factory.Comparators;
import org.eclipse.collections.impl.block.factory.Procedures;
import org.eclipse.collections.impl.factory.Lists;
import org.eclipse.collections.impl.factory.Sets;
import org.eclipse.collections.impl.list.Interval;
import org.eclipse.collections.impl.list.mutable.FastList;
import org.eclipse.collections.impl.math.IntegerSum;
import org.eclipse.collections.impl.math.Sum;
import org.eclipse.collections.impl.math.SumProcedure;
import org.eclipse.collections.impl.test.ClassComparer;
import org.eclipse.collections.impl.test.Verify;
import org.eclipse.collections.impl.test.domain.Key;
import org.eclipse.collections.impl.utility.ArrayIterate;
import org.junit.Assert;
import org.junit.Test;

/**
 * JUnit test suite for {@link UnifiedSet}.
 */
public class UnifiedSetTest extends AbstractMutableSetTestCase
{
    @Override
    protected <T> UnifiedSet<T> newWith(T... littleElements)
    {
        return UnifiedSet.newSetWith(littleElements);
    }

    @Override
    @Test
    public void with()
    {
        Verify.assertEqualsAndHashCode(
                UnifiedSet.newSetWith("1"),
                UnifiedSet.newSet().with("1"));
        Verify.assertEqualsAndHashCode(
                UnifiedSet.newSetWith("1", "2"),
                UnifiedSet.newSet().with("1", "2"));
        Verify.assertEqualsAndHashCode(
                UnifiedSet.newSetWith("1", "2", "3"),
                UnifiedSet.newSet().with("1", "2", "3"));
        Verify.assertEqualsAndHashCode(
                UnifiedSet.newSetWith("1", "2", "3", "4"),
                UnifiedSet.newSet().with("1", "2", "3", "4"));

        MutableSet<String> list = UnifiedSet.<String>newSet().with("A")
                .withAll(Lists.fixedSize.of("1", "2"))
                .withAll(Lists.fixedSize.of())
                .withAll(Sets.fixedSize.of("3", "4"));
        Verify.assertEqualsAndHashCode(UnifiedSet.newSetWith("A", "1", "2", "3", "4"), list);
    }

    @Test
    public void newSet_throws()
    {
        Assert.assertThrows(IllegalArgumentException.class, () -> new UnifiedSet<Integer>(-1, 0.5f));
        Assert.assertThrows(IllegalArgumentException.class, () -> new UnifiedSet<Integer>(1, -0.5f));
        Assert.assertThrows(IllegalArgumentException.class, () -> new UnifiedSet<Integer>(1, 0.0f));
        Assert.assertThrows(IllegalArgumentException.class, () -> new UnifiedSet<Integer>(1, 1.5f));
    }

    @Test
    public void newSetWithIterable()
    {
        MutableSet<Integer> integers = UnifiedSet.newSet(Interval.oneTo(3));
        Assert.assertEquals(UnifiedSet.newSetWith(1, 2, 3), integers);
    }

    @Test
    public void unifiedSetProperSuperSetOfHashSet()
    {
        Assert.assertTrue(ClassComparer.isProperSupersetOf(UnifiedSet.class, HashSet.class));
    }

    @Override
    @Test
    public void add()
    {
        super.add();

        // force rehashing at each step of adding a new colliding entry
        for (int i = 0; i < COLLISIONS.size(); i++)
        {
            UnifiedSet<Integer> unifiedSet = UnifiedSet.<Integer>newSet(i, 0.75f).withAll(COLLISIONS.subList(0, i));
            if (i == 2)
            {
                unifiedSet.add(Integer.valueOf(1));
            }
            if (i == 4)
            {
                unifiedSet.add(Integer.valueOf(1));
                unifiedSet.add(Integer.valueOf(2));
            }
            Integer value = COLLISIONS.get(i);
            Assert.assertTrue(unifiedSet.add(value));
        }

        // Rehashing Case A: a bucket with only one entry and a low capacity forcing a rehash, where the triggering element goes in the bucket
        // set up a chained bucket
        UnifiedSet<Integer> caseA = UnifiedSet.<Integer>newSet(2).with(COLLISION_1, COLLISION_2);
        // clear the bucket to one element
        caseA.remove(COLLISION_2);
        // increase the occupied count to the threshold
        caseA.add(Integer.valueOf(1));
        caseA.add(Integer.valueOf(2));

        // add the colliding value back and force the rehash
        Assert.assertTrue(caseA.add(COLLISION_2));

        // Rehashing Case B: a bucket with only one entry and a low capacity forcing a rehash, where the triggering element is not in the chain
        // set up a chained bucket
        UnifiedSet<Integer> caseB = UnifiedSet.<Integer>newSet(2).with(COLLISION_1, COLLISION_2);
        // clear the bucket to one element
        caseB.remove(COLLISION_2);
        // increase the occupied count to the threshold
        caseB.add(Integer.valueOf(1));
        caseB.add(Integer.valueOf(2));

        // add a new value and force the rehash
        Assert.assertTrue(caseB.add(3));
    }

    @Override
    @Test
    public void addAllIterable()
    {
        super.addAllIterable();

        // test adding a fully populated chained bucket
        MutableSet<Integer> expected = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4, COLLISION_5, COLLISION_6, COLLISION_7);
        Assert.assertTrue(UnifiedSet.<Integer>newSet().addAllIterable(expected));

        // add an odd-sized collection to a set with a small max to ensure that its capacity is maintained after the operation.
        UnifiedSet<Integer> tiny = UnifiedSet.newSet(0);
        Assert.assertTrue(tiny.addAllIterable(FastList.newListWith(COLLISION_1)));
    }

    @Test
    public void get()
    {
        UnifiedSet<Integer> set = UnifiedSet.<Integer>newSet(SIZE).withAll(COLLISIONS);
        set.removeAll(COLLISIONS);
        for (Integer integer : COLLISIONS)
        {
            Assert.assertNull(set.get(integer));
            Assert.assertNull(set.get(null));
            set.add(integer);
            //noinspection UnnecessaryBoxing,CachedNumberConstructorCall,BoxingBoxedValue
            Assert.assertSame(integer, set.get(new Integer(integer)));
        }
        Assert.assertEquals(COLLISIONS.toSet(), set);

        // the pool interface supports getting null keys
        UnifiedSet<Integer> chainedWithNull = UnifiedSet.newSetWith(null, COLLISION_1);
        Verify.assertContains(null, chainedWithNull);
        Assert.assertNull(chainedWithNull.get(null));

        // getting a non-existent from a chain with one slot should short-circuit to return null
        UnifiedSet<Integer> chainedWithOneSlot = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2);
        chainedWithOneSlot.remove(COLLISION_2);
        Assert.assertNull(chainedWithOneSlot.get(COLLISION_2));
    }

    @Test
    public void put()
    {
        int size = MORE_COLLISIONS.size();
        for (int i = 1; i <= size; i++)
        {
            Pool<Integer> unifiedSet = UnifiedSet.<Integer>newSet(1).withAll(MORE_COLLISIONS.subList(0, i - 1));
            Integer newValue = MORE_COLLISIONS.get(i - 1);

            Assert.assertSame(newValue, unifiedSet.put(newValue));
            //noinspection UnnecessaryBoxing,CachedNumberConstructorCall,BoxingBoxedValue
            Assert.assertSame(newValue, unifiedSet.put(new Integer(newValue)));
        }

        // assert that all redundant puts into a each position of chain bucket return the original element added
        Pool<Integer> set = UnifiedSet.<Integer>newSet(4).with(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4);
        for (int i = 0; i < set.size(); i++)
        {
            Integer value = COLLISIONS.get(i);
            Assert.assertSame(value, set.put(value));
        }

        // force rehashing at each step of putting a new colliding entry
        for (int i = 0; i < COLLISIONS.size(); i++)
        {
            Pool<Integer> pool = UnifiedSet.<Integer>newSet(i).withAll(COLLISIONS.subList(0, i));
            if (i == 2)
            {
                pool.put(Integer.valueOf(1));
            }
            if (i == 4)
            {
                pool.put(Integer.valueOf(1));
                pool.put(Integer.valueOf(2));
            }
            Integer value = COLLISIONS.get(i);
            Assert.assertSame(value, pool.put(value));
        }

        // cover one case not covered in the above: a bucket with only one entry and a low capacity forcing a rehash
        // set up a chained bucket
        Pool<Integer> pool = UnifiedSet.<Integer>newSet(2).with(COLLISION_1, COLLISION_2);
        // clear the bucket to one element
        pool.removeFromPool(COLLISION_2);
        // increase the occupied count to the threshold
        pool.put(Integer.valueOf(1));
        pool.put(Integer.valueOf(2));

        // put the colliding value back and force the rehash
        Assert.assertSame(COLLISION_2, pool.put(COLLISION_2));

        // put chained items into a pool without causing a rehash
        Pool<Integer> olympicPool = UnifiedSet.newSet();
        Assert.assertSame(COLLISION_1, olympicPool.put(COLLISION_1));
        Assert.assertSame(COLLISION_2, olympicPool.put(COLLISION_2));
    }

    @Test
    public void removeFromPool()
    {
        Pool<Integer> unifiedSet = UnifiedSet.<Integer>newSet(8).withAll(COLLISIONS);
        COLLISIONS.reverseForEach(each -> {
            Assert.assertNull(unifiedSet.removeFromPool(null));
            Assert.assertSame(each, unifiedSet.removeFromPool(each));
            Assert.assertNull(unifiedSet.removeFromPool(each));
            Assert.assertNull(unifiedSet.removeFromPool(null));
            Assert.assertNull(unifiedSet.removeFromPool(COLLISION_10));
        });

        Assert.assertEquals(UnifiedSet.<Integer>newSet(), unifiedSet);

        COLLISIONS.forEach(Procedures.cast(each -> {
            Pool<Integer> unifiedSet2 = UnifiedSet.<Integer>newSet(8).withAll(COLLISIONS);

            Assert.assertNull(unifiedSet2.removeFromPool(null));
            Assert.assertSame(each, unifiedSet2.removeFromPool(each));
            Assert.assertNull(unifiedSet2.removeFromPool(each));
            Assert.assertNull(unifiedSet2.removeFromPool(null));
            Assert.assertNull(unifiedSet2.removeFromPool(COLLISION_10));
        }));

        // search a chain for a non-existent element
        Pool<Integer> chain = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4);
        Assert.assertNull(chain.removeFromPool(COLLISION_5));

        // search a deep chain for a non-existent element
        Pool<Integer> deepChain = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4, COLLISION_5, COLLISION_6, COLLISION_7);
        Assert.assertNull(deepChain.removeFromPool(COLLISION_8));

        // search for a non-existent element
        Pool<Integer> empty = UnifiedSet.newSetWith(COLLISION_1);
        Assert.assertNull(empty.removeFromPool(COLLISION_2));
    }

    @Test
    public void serialization()
    {
        int size = COLLISIONS.size();
        for (int i = 1; i < size; i++)
        {
            MutableSet<Integer> set = UnifiedSet.<Integer>newSet(SIZE).withAll(COLLISIONS.subList(0, i));
            Verify.assertPostSerializedEqualsAndHashCode(set);

            set.add(null);
            Verify.assertPostSerializedEqualsAndHashCode(set);
        }

        UnifiedSet<Integer> nullBucketZero = UnifiedSet.newSetWith(null, COLLISION_1, COLLISION_2);
        Verify.assertPostSerializedEqualsAndHashCode(nullBucketZero);

        UnifiedSet<Integer> simpleSetWithNull = UnifiedSet.newSetWith(null, 1, 2);
        Verify.assertPostSerializedEqualsAndHashCode(simpleSetWithNull);
    }

    @Test
    public void null_behavior()
    {
        UnifiedSet<Integer> unifiedSet = UnifiedSet.<Integer>newSet(10).withAll(MORE_COLLISIONS);
        MORE_COLLISIONS.clone().reverseForEach(each -> {
            Assert.assertTrue(unifiedSet.add(null));
            Assert.assertFalse(unifiedSet.add(null));
            Verify.assertContains(null, unifiedSet);
            Verify.assertPostSerializedEqualsAndHashCode(unifiedSet);

            Assert.assertTrue(unifiedSet.remove(null));
            Assert.assertFalse(unifiedSet.remove(null));
            Verify.assertNotContains(null, unifiedSet);

            Verify.assertPostSerializedEqualsAndHashCode(unifiedSet);

            Assert.assertNull(unifiedSet.put(null));
            Assert.assertNull(unifiedSet.put(null));
            Assert.assertNull(unifiedSet.removeFromPool(null));
            Assert.assertNull(unifiedSet.removeFromPool(null));

            Verify.assertContains(each, unifiedSet);
            Assert.assertTrue(unifiedSet.remove(each));
            Assert.assertFalse(unifiedSet.remove(each));
            Verify.assertNotContains(each, unifiedSet);
        });
    }

    @Override
    @Test
    public void equalsAndHashCode()
    {
        super.equalsAndHashCode();

        UnifiedSet<Integer> singleCollisionBucket = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2);
        singleCollisionBucket.remove(COLLISION_2);
        Assert.assertEquals(singleCollisionBucket, UnifiedSet.newSetWith(COLLISION_1));

        Verify.assertEqualsAndHashCode(UnifiedSet.newSetWith(null, COLLISION_1, COLLISION_2, COLLISION_3), UnifiedSet.newSetWith(null, COLLISION_1, COLLISION_2, COLLISION_3));
        Verify.assertEqualsAndHashCode(UnifiedSet.newSetWith(COLLISION_1, null, COLLISION_2, COLLISION_3), UnifiedSet.newSetWith(COLLISION_1, null, COLLISION_2, COLLISION_3));
        Verify.assertEqualsAndHashCode(UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, null, COLLISION_3), UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, null, COLLISION_3));
        Verify.assertEqualsAndHashCode(UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, null), UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, null));
    }

    @Test
    public void constructor_from_UnifiedSet()
    {
        Verify.assertEqualsAndHashCode(new HashSet<>(MORE_COLLISIONS), UnifiedSet.newSet(MORE_COLLISIONS));
    }

    @Test
    public void copyConstructor()
    {
        // test copying a chained bucket
        MutableSet<Integer> set = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4, COLLISION_5, COLLISION_6, COLLISION_7);
        Verify.assertEqualsAndHashCode(set, UnifiedSet.newSet(set));
    }

    @Test
    public void newSet()
    {
        for (int i = 1; i < 17; i++)
        {
            this.assertPresizedSet(i, 0.75f);
        }
        this.assertPresizedSet(31, 0.75f);
        this.assertPresizedSet(32, 0.75f);
        this.assertPresizedSet(34, 0.75f);
        this.assertPresizedSet(60, 0.75f);
        this.assertPresizedSet(64, 0.70f);
        this.assertPresizedSet(68, 0.70f);
        this.assertPresizedSet(60, 0.70f);
        this.assertPresizedSet(1025, 0.80f);
        this.assertPresizedSet(1024, 0.80f);
        this.assertPresizedSet(1025, 0.80f);
        this.assertPresizedSet(1024, 0.805f);
    }

    private void assertPresizedSet(int initialCapacity, float loadFactor)
    {
        try
        {
            Field tableField = UnifiedSet.class.getDeclaredField("table");
            tableField.setAccessible(true);

            Object[] table = (Object[]) tableField.get(UnifiedSet.newSet(initialCapacity, loadFactor));

            int size = (int) Math.ceil(initialCapacity / loadFactor);
            int capacity = 1;
            while (capacity < size)
            {
                capacity <<= 1;
            }

            Assert.assertEquals(capacity, table.length, 0.00);
        }
        catch (SecurityException ignored)
        {
            Assert.fail("Unable to modify the visibility of the table on UnifiedSet");
        }
        catch (NoSuchFieldException ignored)
        {
            Assert.fail("No field named table UnifiedSet");
        }
        catch (IllegalAccessException ignored)
        {
            Assert.fail("No access the field table in UnifiedSet");
        }
    }

    @Test
    public void batchForEach()
    {
        //Testing batch size of 1 to 16 with no chains
        UnifiedSet<Integer> set = UnifiedSet.<Integer>newSet(10).with(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
        for (int sectionCount = 1; sectionCount <= 16; ++sectionCount)
        {
            Sum sum = new IntegerSum(0);
            for (int sectionIndex = 0; sectionIndex < sectionCount; ++sectionIndex)
            {
                set.batchForEach(new SumProcedure<>(sum), sectionIndex, sectionCount);
            }
            Assert.assertEquals(55, sum.getValue());
        }

        //Testing 1 batch with chains
        Sum sum2 = new IntegerSum(0);
        UnifiedSet<Integer> set2 = UnifiedSet.<Integer>newSet(3).with(COLLISION_1, COLLISION_2, COLLISION_3, 1, 2);
        int numBatches = set2.getBatchCount(100);
        for (int i = 0; i < numBatches; ++i)
        {
            set2.batchForEach(new SumProcedure<>(sum2), i, numBatches);
        }
        Assert.assertEquals(1, numBatches);
        Assert.assertEquals(54, sum2.getValue());

        //Testing batch size of 3 with chains and uneven last batch
        Sum sum3 = new IntegerSum(0);
        UnifiedSet<Integer> set3 = UnifiedSet.<Integer>newSet(4, 1.0F).with(COLLISION_1, COLLISION_2, 1, 2, 3, 4, 5);
        int numBatches2 = set3.getBatchCount(3);
        for (int i = 0; i < numBatches2; ++i)
        {
            set3.batchForEach(new SumProcedure<>(sum3), i, numBatches2);
        }
        Assert.assertEquals(32, sum3.getValue());

        //Test batchForEach on empty set, it should simply do nothing and not throw any exceptions
        Sum sum4 = new IntegerSum(0);
        UnifiedSet<Integer> set4 = UnifiedSet.newSet();
        set4.batchForEach(new SumProcedure<>(sum4), 0, set4.getBatchCount(1));
        Assert.assertEquals(0, sum4.getValue());
    }

    @Override
    @Test
    public void toArray()
    {
        super.toArray();

        int size = COLLISIONS.size();
        for (int i = 1; i < size; i++)
        {
            MutableSet<Integer> set = UnifiedSet.<Integer>newSet(SIZE).withAll(COLLISIONS.subList(0, i));
            Object[] objects = set.toArray();
            Assert.assertEquals(set, UnifiedSet.newSetWith(objects));
        }

        MutableSet<Integer> deepChain = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4, COLLISION_5, COLLISION_6);
        Assert.assertArrayEquals(new Integer[]{COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4, COLLISION_5, COLLISION_6}, deepChain.toArray());

        MutableSet<Integer> minimumChain = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2);
        minimumChain.remove(COLLISION_2);
        Assert.assertArrayEquals(new Integer[]{COLLISION_1}, minimumChain.toArray());

        MutableSet<Integer> set = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4);
        Integer[] target = {Integer.valueOf(1), Integer.valueOf(1), Integer.valueOf(1), Integer.valueOf(1), Integer.valueOf(1), Integer.valueOf(1)};
        Integer[] actual = set.toArray(target);
        ArrayIterate.sort(actual, actual.length, Comparators.safeNullsHigh(Integer::compareTo));
        Assert.assertArrayEquals(new Integer[]{COLLISION_1, 1, COLLISION_2, COLLISION_3, COLLISION_4, null}, actual);
    }

    @Test
    public void iterator_remove()
    {
        int size = MORE_COLLISIONS.size();
        for (int i = 0; i < size; i++)
        {
            MutableSet<Integer> actual = UnifiedSet.<Integer>newSet(SIZE).withAll(MORE_COLLISIONS);
            Iterator<Integer> iterator = actual.iterator();
            for (int j = 0; j <= i; j++)
            {
                Assert.assertTrue(iterator.hasNext());
                iterator.next();
            }
            iterator.remove();

            MutableSet<Integer> expected = UnifiedSet.newSet(MORE_COLLISIONS);
            expected.remove(MORE_COLLISIONS.get(i));
            Assert.assertEquals(expected, actual);
        }

        // remove the last element from within a 2-level long chain that is fully populated
        MutableSet<Integer> set = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4, COLLISION_5, COLLISION_6, COLLISION_7);
        Iterator<Integer> iterator1 = set.iterator();
        for (int i = 0; i < 7; i++)
        {
            iterator1.next();
        }
        iterator1.remove();
        Assert.assertEquals(UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4, COLLISION_5, COLLISION_6), set);

        // remove the second-to-last element from a 2-level long chain that that has one empty slot
        Iterator<Integer> iterator2 = set.iterator();
        for (int i = 0; i < 6; i++)
        {
            iterator2.next();
        }
        iterator2.remove();
        Assert.assertEquals(UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4, COLLISION_5), set);

        //Testing removing the last element in a fully populated chained bucket
        MutableSet<Integer> set2 = this.newWith(COLLISION_1, COLLISION_2, COLLISION_3, COLLISION_4);
        Iterator<Integer> iterator3 = set2.iterator();
        for (int i = 0; i < 3; ++i)
        {
            iterator3.next();
        }
        iterator3.next();
        iterator3.remove();
        Verify.assertSetsEqual(UnifiedSet.newSetWith(COLLISION_1, COLLISION_2, COLLISION_3), set2);
    }

    @Test
    public void setKeyPreservation()
    {
        Key key = new Key("key");

        Key duplicateKey1 = new Key("key");
        MutableSet<Key> set1 = UnifiedSet.<Key>newSet().with(key, duplicateKey1);
        Verify.assertSize(1, set1);
        Verify.assertContains(key, set1);
        Assert.assertSame(key, set1.getFirst());

        Key duplicateKey2 = new Key("key");
        MutableSet<Key> set2 = UnifiedSet.<Key>newSet().with(key, duplicateKey1, duplicateKey2);
        Verify.assertSize(1, set2);
        Verify.assertContains(key, set2);
        Assert.assertSame(key, set2.getFirst());

        Key duplicateKey3 = new Key("key");
        MutableSet<Key> set3 = UnifiedSet.<Key>newSet().with(key, new Key("not a dupe"), duplicateKey3);
        Verify.assertSize(2, set3);
        Verify.assertContainsAll(set3, key, new Key("not a dupe"));
        Assert.assertSame(key, set3.detect(key::equals));
    }

    @Test
    public void withSameIfNotModified()
    {
        UnifiedSet<Integer> integers = UnifiedSet.newSet();
        Assert.assertEquals(UnifiedSet.newSetWith(1, 2), integers.with(1, 2));
        Assert.assertEquals(UnifiedSet.newSetWith(1, 2, 3, 4), integers.with(2, 3, 4));
        Assert.assertSame(integers, integers.with(5, 6, 7));
    }

    @Override
    @Test
    public void retainAll()
    {
        super.retainAll();

        MutableSet<Object> setWithNull = this.newWith((Object) null);
        Assert.assertFalse(setWithNull.retainAll(FastList.newListWith((Object) null)));
        Assert.assertEquals(UnifiedSet.newSetWith((Object) null), setWithNull);
    }

    @Test(expected = NullPointerException.class)
    public void asParallelNullExecutorService()
    {
        this.newWith(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).asParallel(null, 2);
    }

    @Test(expected = IllegalArgumentException.class)
    public void asParallelLessThanOneBatchSize()
    {
        this.newWith(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).asParallel(Executors.newFixedThreadPool(10), 0);
    }

    @Override
    @Test
    public void getFirst()
    {
        super.getFirst();

        int size = MORE_COLLISIONS.size();
        for (int i = 1; i <= size - 1; i++)
        {
            MutableSet<Integer> unifiedSet = UnifiedSet.<Integer>newSet(1).withAll(MORE_COLLISIONS.subList(0, i));
            Assert.assertSame(MORE_COLLISIONS.get(0), unifiedSet.getFirst());
        }
    }

    @Override
    @Test
    public void getLast()
    {
        super.getLast();

        int size = MORE_COLLISIONS.size();
        for (int i = 1; i <= size - 1; i++)
        {
            MutableSet<Integer> unifiedSet = UnifiedSet.<Integer>newSet(1).withAll(MORE_COLLISIONS.subList(0, i));
            Assert.assertSame(MORE_COLLISIONS.get(i - 1), unifiedSet.getLast());
        }

        MutableSet<Integer> chainedWithOneSlot = UnifiedSet.newSetWith(COLLISION_1, COLLISION_2);
        chainedWithOneSlot.remove(COLLISION_2);
        Assert.assertSame(COLLISION_1, chainedWithOneSlot.getLast());
    }

    @Test
    public void trimToSize()
    {
        UnifiedSet<String> set = UnifiedSet.newSet();
        MutableSet<String> expected = Sets.mutable.empty();

        Interval integers = Interval.fromTo(0, 250);
        integers.each(each ->
        {
            set.add(each.toString());
            expected.add(each.toString());
        });
        ArrayIterate.forEach(FREQUENT_COLLISIONS, each ->
        {
            set.add(each);
            expected.add(each);
        });

        Assert.assertEquals(expected, set);
        Assert.assertEquals(261, set.size());

        MutableList<Integer> toRemove = Lists.mutable.withAll(Interval.evensFromTo(0, 20));

        toRemove.addAll(Interval.oddsFromTo(35, 55));
        toRemove.each(each ->
        {
            set.remove(each.toString());
            expected.remove(each.toString());
        });

        // First assertion to verify that trim does not happen since, the table is already at the smallest required power of 2.
        Assert.assertFalse(set.trimToSize());
        Assert.assertEquals(239, set.size());
        Assert.assertEquals(expected, set);

        Interval.evensFromTo(0, 250).each(each ->
        {
            set.remove(each.toString());
            expected.remove(each.toString());
        });

        // Second assertion to verify that trim happens since, the table length is less than smallest required power of 2.
        Assert.assertTrue(set.trimToSize());
        Assert.assertFalse(set.trimToSize());
        Assert.assertEquals(expected, set);
        Assert.assertEquals(124, set.size());
        expected.each(each -> Assert.assertEquals(each, set.get(each)));

        integers.each(each ->
        {
            set.remove(each.toString());
            expected.remove(each.toString());
        });
        Assert.assertTrue(set.trimToSize());
        Assert.assertFalse(set.trimToSize());
        Assert.assertEquals(expected, set);
        expected.each(each -> Assert.assertEquals(each, set.get(each)));

        set.clear();
        Assert.assertTrue(set.trimToSize());
        Interval.oneTo(4).each(each -> set.add(each.toString()));
        // Assert that trim does not happen after puts
        Assert.assertFalse(set.trimToSize());
        set.remove("1");
        set.remove("2");
        Assert.assertTrue(set.trimToSize());

        set.add("1");
        // Assert that the resized table due to put is the required size and no need to trim that.
        Assert.assertFalse(set.trimToSize());

        Interval.zeroTo(4).each(each -> set.add(each.toString()));
        Interval.oneTo(3).each(each -> set.remove(each.toString()));
        Assert.assertTrue(set.trimToSize());
        Assert.assertEquals(2, set.size());
    }
}